Joint efforts by Inocean and scientists at University of Gothenburg could restore life to the Baltic Sea through the Baltic Deepwater Oxygenation project.

Based on research performed by Professor Anders Stigebrandt at the University of Gothenburg, engineers at Inocean under the management of Vice President, Holger Eriksson, have developed a wind-driven, floating deep-water pump for oxygenation of the vast seabed areas devoid of aquatic life in the Baltic Sea between Sweden and the Baltic countries.

In operation in 18 months

“The first demonstration pump is expected to be operational in about 18 months. After that a more extensive program involving larger deepwater pumps will be deployed,” says Holger Eriksson. “The technology can be scaled up and down and is also suitable for fresh water lakes or salt water fjords with similar problems around the world.

Pilot project shows great results

The idea is to integrate a pump with a floating windmill so that wind power pumps oxygen-rich surface water down to the dead seabed. This provides the prerequisites for the generation of new ecosystems, allowing nature itself to tackle the problematic overproduction of algae. Algae thrive on phosphorous compounds from fertilizer runoffs, killing off the natural flora and fauna of the seabed. The method can be compared to the establishment of wetlands ashore. A pilot project involving this method has given great results.

Expertise from the offshore industry

“At Inocean we see that our experience and technology from the offshore industry can be utilized to accomplish the methods researchers have arrived at,” says Eriksson. “According to plan the demonstrator pump will be located in the waters southeast of Stockholm and placed in a pipe leading 100 meters below the surface, with a 50-metre tower above the surface upon which a wind turbine is mounted. The pump has a capacity of moving 40 cubic meters of water per second. But as inferred our aim is to scale the installation up to achieve an even better effect. That will make it a very interesting method for cleansing bodies of water that have been polluted,” says Holger Eriksson

Could produce electric power as well

Treatment of the deep-sea regions of the Baltic Sea requires around 100 pumps, each with a pumping capacity of 100 m³/s. To materialize such a giant project, financial incentives could be given to the players involved. To accomplish this, the complete field development in the Baltic Sea could most likely consist of units that generate electrical power as well as pump water into the depths. If five groups of 20 floating wind turbines of 5 megawatts (MW) each were installed, 20% of the generated power would be used for pumping and the remainder, amounting to 80 MW, could be transported to land. This would give Sweden an estimated boost of 1.4 TWh of environmentally friendly energy per year.